The amount of time and money people are spending on mobile devices is growing rapidly and yet many businesses don't have a website optimized for mobile — at what cost?

First, the numbers. Mobile traffic currently makes up 10% of global Internet traffic, as shown in the chart below, and next year more people will use mobile phones than PCs to get online, according to Gartner. Purchases made on mobile devices amounted to $6.7 billion in the U.S. last year, or about 8% of total online sales, and are expected to nearly double to $11.6 billion this year. By 2015, U.S. mobile sales are forecast to reach $31 billion.

Yet many businesses have not yet optimized their websites for mobile, frustrating visitors with tricky navigation and slow loading times. Jesse Haines, group marketing manager for Google Mobile Ads, told Mashable that a survey of major advertisers in early 2011 showed only 21% had launched a mobile-friendly site. A 2012 L2 study of the top 100 fashion, beauty, retail, hospitality, and watch and jewelry brands found that only two-thirds had mobile-optimized sites, and yet a third of those did not allow consumers to shop from their sites.

If you're in the business of ecommerce, those figures should help you benchmark what you're already losing in dollars, but a recent survey from Google underlines the damage you might also be doing to your brand by not having your site optimized for mobile.

The survey, which tallied responses from 1,088 U.S. adult smartphone owners, found that:

Mobile sites lead to mobile purchases. This is a no-brainer: Shoppers are more likely to buy a product or service if your site is optimized for mobile. Three-fourths said they are more likely to return to a site in the future if the experience on mobile is good.

If your site isn't optimized for mobile, shoppers will go elsewhere. The majority of participants in the survey said that if they can't find what they're looking for on your site, they'll sooner seek out a competitor's mobile-friendly site instead of switching to a PC to revisit yours.

A bad mobile experience can damage a company's brand. A bad mobile experience can create bad feelings about your company. Nearly half of participants in the survey said they feel frustrated and annoyed when they happen across a site that's not mobile-friendly, and that it makes them feel like a company doesn't care about their business. More than half said a poor mobile experience makes them less likely to engage with a company in the future.

Convinced? We've rounded up some resources to help you make your site suitable for mobile visitors:

Ready To Go Mo?: This Google microsite will help you develop and test a mobile site with Google's own site builder tool, and see how others have done it.

IAB Vendor Directory: Need a developer or agency to help you create a mobile site? You can find one here.

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